UFCThe Ultimate Fighting Championship (UFC) is a U.S.-based mixed martial arts organization, recognized as the largest MMA promotion in the world. The UFC is headquartered in Las Vegas, Nevada and is owned and operated by Zuffa, LLC. This promotion is responsible for solidifying the sport's postion in the history-books.
UFC is currently undergoing a remarkable surge in popularity, along with greater mainstream media coverage. UFC programming can now be seen on FOX, FX, and FUEL TV in the United States, as well as in 35 other countries worldwide.

I think Johnson is a better fight for Amir as he is the sort of guy who won't view Amir as dangerous in the stand up or on the ground. Amir isn't the best, but he really makes people pay who underestimate him.